Some of the largest wintering concentrations of bald eagles in the contiguous 48 states are found along the Mississippi and Illinois rivers. More than 500 of these majestic birds have been counted near the Illinois-Mississippi Rivers confluence as they gather to feed in open water areas. The eagles usually begin to arrive in October and stay until early spring. Several adult eagle pairs remain throughout the year to nest and raise young near the river.
 

Wood ducks commonly nest on Two Rivers National Wildlife Refuge. Males are iridescent chestnut and green, with ornate patterns on nearly every feather; the females have a distinguishing profile and white pattern around the eye. The small waterfowl have a distinct call. The female makes a loud "oo-eek, oo-eek" sound when disturbed and taking flight; males have a thin, rising and falling zeeting whistle. Listen for their call while walking through the flooded forests of the Gilbert Lake division.

Natural historic flood and drought cycles of the Upper Mississippi River were significantly altered by the lock and dam system and thousands of miles of flood control levees. Spiky, unpredictable water levels and the loss of summer low-water periods have reduced wetland habitat quality. In addition, sediment flowing into the river system from upland agricultural areas is filling in important wetlands and impacting water quality.

Two Rivers National Wildlife Refuge works with the rivers using a variety of management techniques to enhance wetland and aquatic habitats in the Upper Mississippi River floodplain for fish and wildlife. Not all techniques are suitable in all areas and the river is often beyond management control. However, over time the Refuge strives to create a natural diversity of wetland and aquatic habitats to benefit native wildlife and fish species.

At the time of European settlement, grassland habitat dominated more than 50 percent of Illinois. Now less than one-tenth of 1 percent of the original tallgrass prairie exists. Historic surveys indicate that grassland communities were once common within the Upper Mississippi River floodplain and included a mosaic of tallgrass prairie on drier sites and wet sedge meadows on wetter sites. Most of the original prairie and wet meadow within the floodplain was converted to agriculture.

Grasslands and wet meadows provide important habitat for many wildlife species of concern, including Henslow's sparrows, grasshopper sparrows, sedge wrens, upland sandpipers, and American woodcock. Fire played an important role historically in creating and maintaining these habitats. Prescribed burning on a periodic basis is essential to maintain plant diversity and habitat quality for wildlife.